Adequate blood circulation is of vital importance to man and to all warm blooded animals. Death or loss of vital body functions occurs several minutes after acute circulatory arrest. There can be a number of causes for this, the most common of which are ventricular fibrillation and asystole, that is to say, conditions in which the heart muscle's periodic contractions stop. These conditions can be primary, that is, they can occur without any apparent reason. Other acute conditions such as blood clots in the pulmonary arteries or in the coronary arteries can secondarily produce the same circulatory effects.
All types of circulatory arrest are treatable in principle, but results are poor. A maximum of 50% of those who suffer such an arrest in the presence of a witness attain normal circulation again after treatment. The others die immediately, as a consequence of their disease, or too long a wait for effective treatment, or inadequate treatment. Of those patients who first regain spontaneous circulation, a large number later die. Circulatory arrest is consequently very difficult to treat, partly due to the short period of time available before damage occurs due to lack of oxygen. Today this treatment most often consists of a combination of different measures such as artificial respiration, compressions of the thorax, administration of cardiac stimulating medication, and short-duration electrical stimulation of the cardiac muscle, so-called defibrillation, by which ventricular fibrillation can often be stopped. By means of external cardiac compressions ("cardiac massage") some degree of blood circulation (5-10% of normal blood flow in vital organs) can be sustained, which along with artificial respiration provides a prolongation of the time period existing before irreversible damage occurs, from 3-4 minutes to a maximum of about 20 minutes. During this time it is in principle possible to go over to more effective forms of treatment. Use of the heart-lung machine, for example, is in the testing stage in certain places in the world. It has been demonstrated that the perfusion pressure of the blood and thereby the blood flow and the amount of oxygen delivered are in direct proportion to the chances of restoring normal circulation and other vital functions following a circulatory arrest. The present invention consists of an apparatus and method for more effective treatment of circulatory arrest, and the invention described here improves treatment of circulatory arrest in a substantially simpler, safer and less expensive but nevertheless much more effective way.